Inflatable form breaker for molded construction

ABSTRACT

An inflatable device for removing the forms from molded concrete or the like construction including a soft, inflatable bladder having two flat, opposite sides which are distendable. An elongated handle is provided from one edge of the bladder for manipulating the bag, and a pressurizing conduit communicates with the interior of the bladder for inflating and deflating it. The sides of the bladder may be covered with flexible sheet material for protecting the bladder against punctures during usage. The conduit is connected to a pressurizing source and a control is provided for inflating and deflating the bladder. After the construction has hardened a wedge or spacer device, in cooperation with the inflatable bladder, may be inserted between the form and the surface of the construction whereby the spacer and bladder are progressively stepped across or down the surface of the molded construction.

Scott v nited States Patent [191 INFLATABLE FORM BREAKER FOR MOLDEDCONSTRUCTION [76] Inventor: Sam C. Scott, 2519 Walnut St.,

Denver, Colo. 80205 [22] Filed: May 21, 1973 [21] Appl. No.: 362,275

[52] US. Cl 254/93 HP, 29/252, 249/66 C, 254/104, 425/436 [51] Int. Cl866i 3/24, B23p 19/04, F161 3/08 [58] Field of Search 254/104, 93 R, 93P;

[56] References Cited UNITED STATES PATENTS 1,752,101 3/1930 Meutsch254/93 HP 2,226,201 12/1940 Freyssinet 254/93 HP 2,396,413 3/1946 Egger254/93 HP 2,480,477 8/1949 Jones 425/436 X 2,644,449 7/1953 Champagne.254/93 HP 2,990,166 6/1961 Walsh 254/93 HP 3,418,767 12/1968 Seeger249/66 C 51' July 9,- 1974 Primary Examiner-Othell M. Simpson Attorney,Agent, or Firm-Richard D, Law

[5 7] ABSTRACT An inflatable device for removing the forms from moldedconcrete or the like construction including a ing it. The sides of thebladder may be covered with v flexible sheet material for protecting thebladder against punctures during usage. The conduit is connected to apressurizing source and a control is provided for inflating anddeflating the bladder. After the construction has hardened a wedge orspacer device,

, in cooperation with the inflatable bladder, maybe inserted between theform and the surface of the construction whereby the spacer and bladderare progressively stepped across or down the surface of the moldedconstruction.

12 Claims, 8 Drawing Figures PATENFEB JUL 91924 sum 1 {IF g PMENIEDJIIL3,822,861-

sum 2 0r 2 This invention is directed to an inflatable device, which maybe used in conjunction with a spacer, for separating a planar form froma molded structure. it is more specifically directed to a form breakerhaving a generally flat, inflatable bladder having soft sides which canbe rapidly inflated and deflated at the interface of the concrete andthe form to strip the forms from the concrete.

ln the past, it has been common practice where possible to use a crane,mechanical wedge, crowbar or other types of wedging devices to force theforms away from the surface of newly formed concrete or othercementitious castable type construction materials, generally causingdamage to the green concrete. Because of the characteristic of theconcrete to adhere tenaciously to the form, particularly to decorativesurfaced concrete, the stripping of the form from the concrete at timeshas proved to be a very difficult task. This is especially true where awall or surface of 'large magnitude is formed and the arrangementnecessitates the use of a large single, built-up form or a plurality oflarge, individual, preassembled forms for forming the structure.

In several pneumatic devices that have been utilized for stripping verysmall area forms from concrete construction, air is introduced directlybetween the form and the surface of the concrete in order to force theform away from the surface. For example, U.S. Pat. No. 2,850,785, issuedSept. 8, 1958 to J. F. Rushing, describes the use of dome-shaped moldingforms (pans or steel dome forms) to form waffle type walls and ceilings.These pans include an air hole through which compressed air may be blownto loosen these pans. These pans are small and once slightly loosened,may be removed. This type of operation is satisfactory where the formsare used in casting the underportion of a ceiling-floor-type structurewhere the small forms are usually convex and the air permits the form tobe uniformly moved at least a short distance downwardly from theconcrete to release the form itself. This type of a process isimpractical where the form defines a relatively large flat surface ofeither a ceiling or wall type object. If air is introduced directlybetween the form and surface of the concrete in this type ofconstruction, the air will rapidly move across only a portion of thesurface to the edge where it will escape.

To counter this type of problem, a flat, noninflatable, disc-type objecthas been suggested, which is cast directly with the concrete and heldagainst the form during the pouring process, U.S. Pat. No. 3,151,374,issued Oct. 6, 1964 to M. E. Kersten. A stem passes directly through theform to the outside where, upon the curing of the concrete, a pneumaticsource is connected to the stem which expands the disc a short distanceto break the form, at least in that particular small area, away from'theconcrete surface. Because of the necessary small size of the disc andthe fact that-it cannot be moved across the surface, either a largenumber of the discs must be incorporated in the form or this device canonly be used in very small castable structures, such as in thefabrication of cinder blocks or concrete blocks. Further, these leave animpression in the concrete surface.

Inflatable disc-like bladders have been placed in the mold with theconcrete poured on the bladders; see

U.S. Pat. No. 2,480,477, issued Aug. 30, 19.49, to F. H. Jones and U.S.Pat. No. 3,418,767, issued Dec. 31, 1968 to F. Seeger. The impression ofthe bladder is left in the concrete, and such bladders are useful foronly small, pan-like molds. g 7

1n the construction of large, single wall-type structures such asreservoirs, tanks and buildings, it is absolutely necessary that anentire section be poured at one time to form a monolithic structure ofuniform consist ency and color. In this type of construction, literallythousands of the disc-like inflatable devices would have to be installedin the forms which would be impractical, both from a cost standpoint aswell as a time consuming operation of individually inflating each unitin series or simultaneously, and their image might not be desirable inthe surface of the concrete.

Some mechanical tools are available for removing forms from concretestructures, and these generally require a longer curing time forconcrete since they tend to break or mar green concrete. A strippingtool is shown in U.S. Pat. No. 3,316,607, issued May 2, 1967 to S. J.Kroll, which utilizes a concrete contacting cap. This cap extendsthrough the form and concrete is cast against it. The cap leaves animpression on the concrete surface, and unless the concrete sets hard,will leave an indent when the form is stripped. Since it has only asmall bearing surface, many of the tools must be used for each formsection.

Large concrete tank casting forms with removal apparatusis shown in U.S.Pat. No. 3,539,146 issued Nov. 10, 1970 to W. L. Smith. The strippingdevice includes pistons for moving inner and outer forms away from eachother to expose the cast tanks. This type of device is limited as tosize and shape.

The present invention, therefore, is directed to a very simple andeconomical device requiring only a single unit for stripping forms fromthe cast cementitious structure.

Another object of the present invention is to provide a form strippingdevice which can be easily inflated and deflated and may be used inconjunction with a spacer so that the inflatable device and the spacermay be progressively positioned in alternate fashion across or down thesurface of the construction to rapidly strip the form from the surface.

Another object of the present invention is to provide an inflatable formstripping device which includes a manipulative handle so that the unitmay be used in stripping the forms from vertical as well as horizontaltype construction.

A still further object of the present invention is to provide aninflatable form stripping device which can be used with any type offluid pressurizing medium which is readily available at the constructionsite.

A still further object of the present invention is to provide alightweight, easily portable form breaker which is both economical tomanufacture and simple to operate.

Another object of the invention is to provide an inflatable strippingtool which reduces the labor of removing forms from the concrete withoutdamage to the concrete. I

The present invention includes an inflatable bladdertype form strippingdevice in one form, which may be used in conjunction with a spacerelement, for progressively stripping forms from east masonryconstruction. The bladder is preferably formed in rectangular shapehaving two planar side members which are joined together around theirentire periphery to form a sealed inflatable chamber or bag. Anelongated handle, which is attached to a clamping means, is connected bythe clamp to one edge of the bladder for the purpose of being able tomove the bladder across or down the surface of the construction by meansof the elongated handle. In one form, to protect the flexible tube orconduit for pressurizing the bladder, the tube is inserted through theelongated handle and communicates with the interior of the bladder.Thus, the handle protects and armors the tube to prevent pinching orseparation while a single elongated member is connected to the bladderfor easy control and manipulation of the bladder in the form breakingoperation. In another form, the tube is merely extended along theoutside of the handle. The conduit can be connected to an air compressoror pump by means of a control device such as a simple thumb controlledopening or three-way control valve. With the valve in one position, orthe thumb hole closed, pressure can be applied to the bladder and withthe control in the opposite position, or the thumb hole open, thebladder can be deflated. The bladder may be connected directly totheinlet of the air compressor of pump and by a three-way valve rapidlydeflated. Thus, a slow inflation and deflation of the bladder ispossible or a rapid pulsing of the bladder is possible depending uponthe type of form breaking operation which is desired.

The spacer device used with the bladder can be either a separateelement, such as an elastomeric wedge, or can be a block with a holepassing therethrough so that the block can be slidably positioned on theelongated handle of the bladder. In either configuration, as the bladderis inserted between the form and concrete surface and inflated, thespacer is moved toward the bladder. This retains the form spaced fromthe concrete surface permitting the bladder to be deflated and movedforward toward the interface of the form and concrete surface. Thiscycle may be repeated to expand the bladder and further separate theform. In this alternating, sequentially-stepped process, the bladder andspacer are moved progressively across or down the surface of the caststructure to easily and rapidly remove the form from the surface. Whenmade of elastomeric material, damage to green concrete is minimized.

Other features of this invention will appear in the followingdescription and appended claims, reference being made to theaccompanying drawings forming a part of the specification wherein likereference characters designate corresponding parts in the several views.

FIG. 1 is a perspective view of one form of inflatable breaker of thepresent invention, showing an elongated handle attached to one edge ofthe bladder;

FIG. 2 is a cross section view of the bladder of FIG. 1 taken along thesection lines 22; the shape of the bladder in the inflated configurationis shown in the dashed lines;

FIG. 3 is a pictorial sectional view which shows a concrete structureand form partly separated by a spacer with a form breaker of the presentdevice inserted between the form and the surface of the concrete;

FIG. 4 is a sectional view of the structure shown in FIG. 3 with theform breaker inflated to further separate the form from the concrete andthe spacer positioned to hold the form in its separated position;

FIG. 5 is a side view of another embodiment of the present inventionshowing the spacer mounted for slidable movement on the handle of theform breaker;

FIG. 6 is a schematic view of one form of control arrangement for thedevice of the invention;

FIG. 7 is a front elevational view of a modified form of the invention,using a detachable solid handle; and

FIG. 8 is a side elevational view of the device of FIG. 7.

Turning now more specifically to the drawings, in FIG. I an inflatableform breaker, shown generally by numeral 10, has a soft, inflatablebladder 11 and elongated handle 12. The bladder 11 includes two flat,planar sides 13, 14 which are sealed together around their entireperiphery to form an imperforate bladder 11. In one form, a sheet ofsoft elastomeric material is folded and the open edges sealed shut.

A clamping or backing device 15, such as an elongated, U-shaped channel,can be attached to one edge of the bladder 11 by means of fasteners 16,such as bolts, sewing or rivets passing through an enlarged edge of thebladder.

The upper edge of the bladder 11, which is attached to the clamp 15, maybe formed as an elongated reinforced section 17 which includes anembedded stiffening member 18 which can be molded integrally with thebladder. The handle 12 is securely attached at right angles to thesurface of the clamp device 15. If desired, a flexible sheet of toughmaterial 19, which can be metal such as steel or aluminum or one of thetough (generally reinforced) plastics can be arranged around the outersurface of the bladder 11 to protect it and prevent punctures duringusage. This may be a simple sleeve or a sheet folded over the bladder.

A hose or conduit 20 connected to a pressurizing source such as acompressor or hydraulic pump (not shown) passes through the handle 12and communicates directly with the interior of the bladder 11, FIG. 6. Acontrol device, such as a three-way valve 28, connected in the tube 20between the pressurizing source or compressor 29 and the bladder 11,permits inflation through line 30 and quick deflation through line 31connected to the inlet of the compressor. When the bladder 11 isinflated, the sides l3, 14 of the bladder 11 take the expanded positionas shown by the dotted lines in FIG. 2. Thus, when inflated, the widthof the device 10 is greatly increased over the original width of thebladder Ill. Also, nominal pressure may be used to inflate the bladder,i.e., l030 psi, so that inexpensive, light weight components may beused.

As shown in FIGS. 3 and 4, a concrete wall 21 has been cast in place byuse of a form 22. In using the inflatable form breaker of the presentinvention, an elastomeric spacer member 23 which may have theconfiguration of a wedge or the like or a rectangular block may beinserted at the upper edge of the formed structure between the form 22and front surface of the cast wall 21. With the form partly separatedfrom the concrete, the inflatable form breaker device 10, in thedeflated configuration, is inserted as far as possible into theinterface between form and concrete surface. The bladder 11 is inflatedto its fully expanded configuration as shown in FIG. 4. If desired, thepressurization of the bladder 11 can take place in a slow operation itis possible to pulse or rapidly expand and contract the bladder 11 togreatly accelerate the operation of removing the form from the concretestructure.

As the bladder is expanded, as shown in FIG. 4, the wedge or spacerfalls by gravity to the point where it is wedged between the form andthe concrete surface. As the bladder is deflated, the form is held inthe separated position (i.e., the gain due to the inflated bladder) bythe spacer so that the form breaker may again be repositioned downwardlyand then expanded with the spacer moving further downwardly. Thus, inalternating progressive steps, the breaker and spacer may be moved downacross the entire surface of the structure so as to completely separatethe form from the concrete surface. By progressively moving in stepwisefashion horizontally across the surface of the construction,

the entire form may be worked loose and separated from the concretesurface and allowing the form to be removed.

If desired, the spacer element 26 may include a central bore so that thespacer 26 may be positioned over the handle 12'of theform breaker 10.Thus, the spacer 26 can slidably move along the handle 12 so that thespacer, during the usage of the form breaker, will automatically beguided by the handle instead of free falling during operation. Thespacer may be made of elastomeric material, wood or the like.

In horizontal type construction, where the form is to be broken awayfrom the undersurface of a cast concrete ceiling, it is intended thatthe spacer member 23 would have an elongated handle 24 attached for thepurpose of permitting the spacer to be repositioned across the surfaceof the form and concrete in the same manner as the form breaker 10 ismoved across the surface by means of the handle 12. If the spacer 26 ismounted for slidable movement on the handle 12, the individual handle 24for the spacer 26 can be mounted in parallel by suitable brackets 25 sothat it can be slidably moved with respect to the handle 12.

The modification of FIGS. 7 and 8 includes a bladder 30, which isinflatable by means of an air line 31, and an outer flexing covering 32of tough, resilient synthetic plastic such as polyurethane sheet,polypropylene sheet, nylon mesh reinforced polyethylene, otherreinforced plastics, etc. The covering 32 is a sheet folded over thebladder and is secured together at its open side 33 by means of a metalclamp means 34. The clamp is secured to the covering by means of rivets37 or the like. The sides of the covering are closed by clamp members 39held by rivets 40 or the like. The clamp members 39 are spaced from theupper clamp member 34 to permit the sides to swing inwardly as thebladder is inflated. This arrangement encloses the bladder in a toughresilient covering, but permits inflation and deflation of the same. Thesides protect the edges of the inflatable member and/or its covering andaids in manipulating the inflatable member into position for use.

A rigid handle support 42 is secured by welding or otherwise to theclamp member 34, generally centrally thereof. A pair of U-bolts 43 withwing nuts 44 are ar- 6 ranged to releasably secure a handle 45 therein.The handle 45 may be long as necessary for the particular concrete formsbeing removed from the concrete, and may be made of solid or tubularmaterial. Wooden handles are satisfactory, as are aluminum, magnesium,etc. solid or tubular stock.

= The air line 31 is connected to an open sided pop-it valvearrangement, shown generally by numeral 46, which includes a reliefvalve 47 and a hole 48. An air line 49 from a compressor (not shown)supplies air to the air line.

For using this embodiment, the handle is attached to the handle supportand tightened in place. The air line 49 is connected to a compressor.The breaker is then placed in between the form and the concrete, asexplained above, with the wedge holding the form from the top of theconcrete. .With the air compressor providing air to tube 49, by closingthe hole 48 with a thumb or finger, air pressure fills the bladderexpanding it. Only about 10-30 pounds per square inch are necessary forsufficient inflation to break the form away from the concrete.Therefore, a small hole is easily covered by a thumb and such lowpressure is easily held. The pressure relief valve 47 preventsoverinflation of the bladder. The bladder is deflated easily by removingthe thumb from the hole. Inflation is achieved by again placing thethumb over the hole. Thus, the bladder may be easily inflated anddeflated for breaking a form away from the concrete. Also, the state ofinflation is easily controlled by using a thumb for partially blockingthe opening.

In the embodiments of the invention described herein, a satisfactorysize of bladder is one in which the width of the bladder, which is thelong dimension, may be 16 to 18 inches while the depth of the bladder,or the short dimension, is approximately 6 to 12 inches. With thesedimensions, the bladder may easily fit between rows of tie wires throughthe forms. Other sizes may obviously be used. The rigid handle may be ofany length which is sufficient to move the form breaker from edge toedge across or down the form for the structure. The bladder 11 may bemade from any flexible, elastomeric material, (preferably very tough andpuncture resistant) such as synthetic plastics (for example,polyurethane, polypropylene, etc.), synthetic rubbers or natural rubberwhich is air impermeable. The clamp device 15 and handle 12 can beformed from any suitable lightweight material such as aluminum,magnesium, fiberglass or plastics which can provide the necessaryrigidity, yet be lightweight to permit a portable operation. The handleand meansfor holding the bladder must be rigidly connected, to permitmovement of the bladder to the desired point of use, and preferably inthe proper configuration, i.e., extending forwardly from the handle. Theside clamps also aid in this.

While an inflatable form breaker device has been shown and described indetail, it is obvious that this invention is not to be considered asbeing limited to the exact form disclosed and that changes in detail andconstruction may be made therein within the scope of the inventionwithout departing from the spirit thereof.

I claim: 1. An inflatable device for separating forms from eastcementitious construction, said device comprising:

a. a flexible, inflatable bladder means capable of being expanded from agenerally flat, deflated configuration to an inflated configuration,said bladder means having a pair of flat planar sides in face engagementwhen deflated and connected to each other around their peripheral edges;

b. rigid backing means extending along at least one side of said bladdersupporting said bladder for manipulation between a form and a castcementitious construction; I

c. tubular handle having holding means for attaching said handle to saidrigid backing means; and

d. conduit means communicating with the interior of said bladder meansinclusive of control means whereby said bladder means can be changedfrom the deflated to the inflated configuration as desired.

2. An inflatable device as defined in claim 1, being furthercharacterized by spacer means insertable between said form and a surfaceof said cementitious construction, whereby said form can be separatedfrom said construction by alternatively and progressively positioningsaid spacer means and said bladder means across the surface of saidconstruction.

3. An inflatable device as defined in claim 2, wherein said spacer meansis arranged for slidable movement on said tubular handle whereby thewedge means can move toward said bladder means when said bladder isextended to the inflated position holding the form spaced from thesurface of the cementitious construction when the bladder is deflatedand moved forward.

4. An inflatable device as defined in claim 2, wherein said handle is ofsufficient length to progressively position said bladder from edge toedge of said cementitious construction.

5. An inflatable device as defined in claim 2, wherein said spacer meansis formed of elastomeric material.

6. An inflatable device as defined in claim 2, wherein said spacer meansincludes an elongated handle which is of sufficient length toprogressively position said spacer means across the surface of the castcementitious construction.

7. An inflatable device as defined in claim 2, wherein said spacer meansis reciprocably mounted on said tubular handle and moves downwardly bygravity when said tubular handle is held vertically.

8. An inflatable device as defined in claim 1, wherein said controlmeans is arranged for alternately connecting said conduit to acompressor inlet and outlet for rapidly changing said bladder means fromthe inflated to the deflated configuration.

9. An inflatable device as defined in claim 1, wherein said controlmeans is an opening in said conduit arranged to be opened and closed bya digit of the user.

10. An inflatable device as defined in claim 1, wherein said controlmeans is a three way valve.

11. An inflatable device as defined in claim 1, wherein one said backingmeans includes clamp means for said bladder.

12. An inflatable device as defined in claim 1, wherein said bladder isof a length to easily fit between rows of tie wires through the forms.

1. An inflatable device for separating forms from cast cementitiousconstruction, said device comprising: a. a flexible, inflatable bladdermeans capable of being expanded from a generally flat, deflatedconfiguration to an inflated configuration, said bladder means having apair of flat planar sides in face engagement when deflated and connectedto each other around their peripheral edges; b. rigid backing meansextending along at least one side of said bladder supporting saidbladder for manipulation between a form and a cast cementitiousconstruction; c. tubular handle having holding means for attaching saidhandle to said rigid backing means; and d. conduit means communicatingwith the interior of said bladder means inclusive of control meanswhereby said bladder means can be changed from the deflated to theinflated configuration as desired.
 2. An inflatable device as defined inclaim 1, being further characterized by spacer means insertable betweensaid form and a surface of said cementitious construction, whereby saidform can be separated from said construction by alternatively andprogressively positioning said spacer means and said bladder meansacross the surface of said construction.
 3. An inflatable device asdefined in claim 2, wherein said spacer means is arranged for slidablemovement on said tubular handle whereby the wedge means can move towardsaid bladder means when said bladder is extended to the inflatedposition holding the form spaced from the surface of the cementitiousconstruction when the bladder is deflated and moved forward.
 4. Aninflatable device as defined in claim 2, wherein said handle is ofsufficient length to progressively position said bladder from edge toedge of said cementitious construction.
 5. An inflatable device asdefined in claim 2, wherein said spacer means is formed of elastomericmaterial.
 6. An inflatable device as defined in claim 2, wherein saidspacer means includes an elongated handle which is of sUfficient lengthto progressively position said spacer means across the surface of thecast cementitious construction.
 7. An inflatable device as defined inclaim 2, wherein said spacer means is reciprocably mounted on saidtubular handle and moves downwardly by gravity when said tubular handleis held vertically.
 8. An inflatable device as defined in claim 1,wherein said control means is arranged for alternately connecting saidconduit to a compressor inlet and outlet for rapidly changing saidbladder means from the inflated to the deflated configuration.
 9. Aninflatable device as defined in claim 1, wherein said control means isan opening in said conduit arranged to be opened and closed by a digitof the user.
 10. An inflatable device as defined in claim 1, whereinsaid control means is a three way valve.
 11. An inflatable device asdefined in claim 1, wherein one said backing means includes clamp meansfor said bladder.
 12. An inflatable device as defined in claim 1,wherein said bladder is of a length to easily fit between rows of tiewires through the forms.